(1) Field of the Invention
This invention relates to an image control apparatus, and more particularly to an image control apparatus for controlling image monitoring.
(2) Description of the Related Art
Recently, due to the rapid development of the image monitoring technique, it is already a technique in the practical use to perform image monitoring by using images compressed by e.g. MPEG, store the monitored images, and distribute such images via a network. Further, with an increase in the volume of storage media, it is also carried out to store image data recorded over a relatively long time period in real time.
However, even if the image monitoring is carried out over a long time of several to several tens of days to store monitored images, it takes immense time to retrieve a desired image from these recorded images.
Therefore, the development of a user-friendly image monitoring technique is even more desired, which is able to extract necessary portions from the recorded images, or record only necessary portions of the recorded images.
Under such circumstances, there has been developed a technique of detecting an event, such as a person, from monitored images. For example, Japanese Laid-Open Patent Publication (Kokai) No. 10-302171 has proposed to additionally carry out a detecting process on images inputted to an MPEG encoder to detect general changes in images, such as differences in background images, to thereby detect a meaningful change (e.g. intrusion of a person) in the images, and based on results of the detection, control recording/non-recording of an MPEG stream of images. This makes it possible to reduce the required capacity of storage media and perform efficient image retrieval.
However, in the general image detection control including the above-described conventional technique, numerical values (of parameters) indicative of an event to be detected, are manually set by an operator who monitors images, individually and separately according to each desired event to be detected. Therefore, this control technique requires all adjustments or configurations to be effected by manual operations, which makes the technique inconvenient to carry out and difficult to perform quantitative configurations. Further, when the point or site for monitoring is changed, the originally set parameters are no longer the optimal ones, which makes it difficult to maintain the image quality.
Thus, the conventional image monitoring technique has failed to provide an efficient way of setting parameters for event detection, which degrades the accuracy of event detection, and hence decreases reliability of the same.